Diastereoselective synthesis of spiro[cyclopropane-1,3′-indolin]-2′-ones through metal-free cyclopropanation using tosylhydrazone salts

Transition metal-free diastereoselective cyclopropanation of 3-methyleneindolin-2-ones using tosylhydrazone salts as a safe alternative to diazo-compounds was achieved in high yields. All the synthesized compounds were evaluated for their biological activity against three different human cancer cell lines DU-145 (prostate cancer), Hela (cervical cancer) and A-549 (lung cancer). Compounds 3b and 3i exhibited promising anticancer activity (IC50 < 10 μM) against the studied cell lines.